This work is an investigation of carbohydrate metabolism and of its inborn errors. It includes an intensive investigation of the control mechanisms in glycogen metabolism, in gluconeogenesis and in glycolysis. During the present year, our efforts will be concentrated on the elucidation of the reactions by which the newly discovered fructose 2,6-bisphosphate is synthesized and degraded in the liver and how these reactions are influenced by glucose and glucagon. Biopsies of patients with glycogen storage disease, lysosomal diseases, lactic acidosis, fructose intolerance, and galactosemia will be analyzed from the biochemical and morphological points of view.